VTOL and V/STOL aircraft take off vertically, fly horizontally, and land either vertically or horizontally. Hardware cost (both procurement and maintenance) has been traditionally high due to the complexity of the lifting system, safety systems, conversion system and need for redundancy. Undesirable propulsive cruise efficiency often results from performance compromises made to ensure sufficient lift thrust and minimal damage to airport surfaces. It also results from additional weight of redundant systems and oversized engines. This lower cruise efficiency often yields a range that is not sufficiently better than that of helicopters. In order for VTOL fixed wing aircraft to be commercially viable, there is a need for engines that enable safe and efficient vertical takeoff, sustain horizontal flight, land safely with one or more engines out, operate quietly in metropolitan areas, meet emissions requirements, and minimize erosion of landing and take-off surfaces.